The present invention relates to a method for recognizing similarly recurring patterns of notes in a piece of music, which contains note sequences distributed on parallel channels.
The recognition of recurring note patterns in pieces of music, e.g. loops, riffs, phrases, motifs, themes, verses, refrains, transitions, movements etc., has become an extensive field of research in recent years with specific and promising technical applications. Some examples of application to be mentioned are the automated analysis of musical structures in pieces of music in computer-aided recording studio, audio workstation and music production environments, which must be based on a reliable music recognition for archiving and sorting purposes as well as the resynthesis of existing note patterns into new compositions. A further specific technical application is the analysis and indexing of large music data banks, e.g. of music archives or online music shops, according to identifiable note patterns for the new field of music information retrieval (MIR), for example, to be able to process “fuzzy” user queries in an automated manner, code word “query by humming”
A wide variety of methods have already been proposed in the past for pattern recognition in single-channel pieces of music that also adopt concepts from other fields of pattern recognition such as “string matching” techniques from the field of DNA sequence analysis, e.g. as in Kilian Jürgen, Hoos Holger H.: “MusicBLAST—Gapped Sequence Alignment for MIR”, International Conference on Music Information Retrieval (ISMIR), 2004. String matching methods are frequently based on the use of dynamic programming algorithms for the alignment and the similarity comparison of note sequences, cf. e.g. Hu Ning, Dannenberg Roger B., Lewis Ann L.: “A Probabilistic Model of Melodic Similarity”, Proceedings of the ICMS, 2002.
In Hsu Jia-Lien, Liu Chih-Chin, Chen Arbee L. P.: “Discovering Nontrivial Repeating Patterns in Musical Data”, IEEE Transactions on Multimedia, vol. 3, no. 3, 2001, the use of a correlation matrix, which allows nontrivial, i.e. not excluding one another, identically recurring patterns in a channel to be detected, is proposed specially for the recognition of identically recurring note patterns for the purposes of music analysis and MIR.
All methods known hitherto have the characteristic that they respectively analyse each channel of a multi-channel piece of music separately. The inventors of the present method have recognized that there is a significant disadvantage in the known methods, because structure information contained specifically in the musical parallelism of the channels, i.e. their rhythmic, melodic and polyphonic context, are completely ignored thereby, and this results in the unsatisfactory rate and quality of recognition of the known methods.
Therefore, there is continuous demand for an improved method of pattern recognition for multi-channel pieces of music. The aim set by the invention is to provide such a method.